ul li {
    float: left;
    list-style-type: none;
    padding-left: 50px;
    border: 1px solid pink;
}
.add{
    padding-left: 20px;
}
.tabsbox{
    border:1px solid red;
}
/* .firstnav{
    border-bottom:1px solid red;
} */
.liactive{
    border-bottom: none;
}
section{
    display: none;
    /* 先全部隐藏 */
}
.conactive{
    display: block;
}
.tabadd span{
    background-color: pink;
}